This series implement the initial Suspend-To-Idle support for the Raspberry Pi, which was a long time on my TODO list [1]. The changes allow to suspend and resume the Raspberry Pi via debug UART. The focus is on the BCM2835 SoC, because it's less complex than its successors and have enough documentation. The series is a loose collection of fixes and improvements. So cherry-picking should be fine. Test steps: - configure debug console (pl011 or mini UART) as wakeup source - send system to idle state echo freeze > /sys/power/state - wakeup system by console traffic The implementation isn't perfect and contains workarounds like patch 4 and 9. So there is still room for improvements, but at least the system won't freeze forever as before [2]. Here are some figures for the Raspberry Pi 1 (without any devices connected except of a debug UART): running but CPU idle = 1.67 W suspend to idle = 1.33 W The series has been tested on the following platforms: Raspberry Pi 1 B Raspberry Pi 3 A+ Raspberry Pi 3 B+ Known issues: - currently it's not possible to power down the USB domain [3] - there seems to be an issue with the DWC2 suspend handling [4] [1] - https://github.com/lategoodbye/rpi-zero/issues/9 [2] - https://bugzilla.redhat.com/show_bug.cgi?id=2283978 [3] - https://github.com/raspberrypi/firmware/issues/1894 [4] - https://lore.kernel.org/linux-usb/3fd0c2fb-4752-45b3-94eb-42352703e1fd@xxxxxxx/T/ Stefan Wahren (11): firmware: raspberrypi: Improve timeout warning mailbox: bcm2835: Fix timeout during suspend mode pmdomain: raspberrypi-power: Adjust packet definition pmdomain: raspberrypi-power: Avoid powering down USB irqchip/bcm2835: Enable SKIP_SET_WAKE and MASK_ON_SUSPEND drm/vc4: hdmi: Handle error case of pm_runtime_resume_and_get drm/vc4: hdmi: Disable connector status polling during suspend usb: dwc2: debugfs: Print parameter no_clock_gating usb: dwc2: Skip clock gating on Broadcom SoCs serial: 8250_bcm2835aux: add PM suspend/resume support ARM: bcm2835_defconfig: Enable SUSPEND arch/arm/configs/bcm2835_defconfig | 2 -- drivers/firmware/raspberrypi.c | 3 ++- drivers/gpu/drm/vc4/vc4_hdmi.c | 18 +++++++++++++++++- drivers/irqchip/irq-bcm2835.c | 4 +++- drivers/mailbox/bcm2835-mailbox.c | 3 ++- drivers/pmdomain/bcm/raspberrypi-power.c | 17 ++++++++++++----- drivers/tty/serial/8250/8250_bcm2835aux.c | 23 +++++++++++++++++++++++ drivers/usb/dwc2/debugfs.c | 1 + drivers/usb/dwc2/params.c | 1 + 9 files changed, 61 insertions(+), 11 deletions(-) -- 2.34.1
